Concentration of phosphate-bearing minerals



Patented Dec. 2a, 1937 2 103 2 3 UNITED STATES PATENT OFFICE CONCENTRATION OF PHOSPHATE-BEARING MINERALS Francis X. Tartar-on and James B. Duke, Mulberry, Fla... assignors to Phosphate Recovery Corporation, New York, N. Y., a corporation of Delaware No Drawing. Application February 4, 1937.

' Serial No. 124,040

I 40 Claims. (Cl. 209-49) ,5 The'presen't invention relates to the concenbe dissolved in alcohol pricnto use, or the bone 5 tration of phosphate-bearing minerals and is oil may be dissolved in alcohol prior to its treatherein illustrated in connection with the examment by the acid.

pies given as applied to the concentration of If the product resulting from the aforemen- Florida phosphate rock. tioned acid treatment of bone oil is thereafter According to the invention, the phosphatetreated with water so as to extract its water- 10 bearing mineral is concentrated by procedures soluble fraction, this extracted fraction may also which may be said to constitute an inverse of the be caused to efi'ect separation of silicious gangue usual procedures of concentration. In concenfrom phosphatic material, which fact seems to tratl'ng the mineral by flotation in accordance indicate that it is one or several of the pyridine with the present invention, for example, it is the and amine bases pre nt i bone One 15 silicious gangue which is caused to accumulate in Several of the impurities associated with these the i'roth, which is removed as a tailing or waste bases, which is efie i in Such p fl product, leaving the greater proportion of the Moreover, it has further been found that the samev phosphate values in the non-floated material as sep rating ff on i i i us gansue may b a concentrate. And in concentrating the mineral p o y e p y g crude quinoline in asso- 20 by tabling, it is the sillcicus gangue which comes ciation with an activating agent; quinoline being oil the side of the table, the phosphate values a substance also present in bone oil, but like coming oil the end of the table. Such inverse pyridine alsocapable ofbeing derived from coal Procedures ave been found possible by the use tar. As in the case of bone oil, the activating of certain substances hereinafter described. A agent employed with crude quinoline may be 25} pulp of theore'containing the phosphate-bean an acid forming a distinctly acid solution with ing mineral is agitated in the presence of these water or one of certain inorganic salts having an substanceathe silicious gangue .being thereafter acid reaction in water. i separated from the phosphatic material by fiota- The use of an activating agent is apparently tion, by tabling, or in any other manner. essential to the process ofthe present invention, 30

We have found that silicious ganguemay be the silicious gangue being probably so condifloated away or otherwise separated from phostioned by such agent that it is enabled to propn atie material by the use of bone oil, it there erly react with the bone oil or other collector is employed in conjunction with that substance employed. When either acid or salt is used as an activating agent which causes the bone oil to the activating agent, the p lp is undoubtedly 0f 5 have a preferential aiilnity for such gangue. As an acid character, although a decidedly acid pulp the activating agent, any acid may be used which, is not necessary, particularly in the case of a salt. when mixed with water, iorms a-distinctly acid Moreover, caustic soda may in certain cases be solution readily titratable with an aqueous soluused alongw h h other agentsy W lltion of a base, satisfactory results having been known frother may also be used, and mineral 40 obtained with sulphuric acid, sulphurous acid, oil may be used as a cooperating collector. hydrochloric acid, hydrofluoric acid, hydrofluor- The separation of silicious gangue from phos- J silicic acid, arsenic acid, selenic acid, acetic acid, phatic material ascarried out with the aid of and lactic acid. In addition to such acids, we the substances above designated enables excelhave found that some inorganic salts reacting lent results to be obtained with relation to both 45 acid in solution with water are useful, the most content and recovery of phosphate values in the ei'lective including sodium silicofluoride, ammoconcentrate or material remaining after the nium silicofluoride, 'stannic chloride, phosphorus separation, the process of the present invention trichloride, silicon tetrachloride, ,thionyl chlobeing almost identical in mechanical characterride, and potassium bisulphate. It is uncertain, istics with the usual processes of separating the 50 however, whether the activating eiiect of these phosphate values. In the same manner the pulp salts is wholly due to their acid reaction, since thickens in the preliminary operation of mixing others also reacting acid have proved totally init with the reagents. And when the subsequent eflective. step of separating the silicious gangue is carried In carrying out the invention, the bone oil and out by froth flotation-there is obtained the same 55 the activating agent may be added separately type of froth float, whichis removed in the usual to the pulp, best results being obtained in most manner in a very short period of time. On the cases when the activating agent is added after other hand, whereas by increasing the amount the bone oil. of collector the grade of concentrate is lowered This application is a continuation in part of application Serial No. 90,154, filed July 11, 1936, itself a continuation'in part of application Serial No. 45,598,}flled October 18, 1935.

As "an alternative procedure, the bone may first be treated with an acid of the aforemenployed without further addition of activating agent to the pulp. If desired, such product may and the recoveryoi values made higher when it be largely deslimed, its desliming greatly mini mizing the consumption of the reagents. Ordinarily, the crude ore is first subjected to a preliminarygrinding operation and thereafterbone oil obtained from the Texas Chemical Company and then 18.4 lbs. per ton of concentrated screened or classified to remove all particles other than those desired. The undersize may then be deslirned, andthe oversize reground, deslimed, and added to the deslimed undersize; or the oversize may be reground, added to the undeslimed undersizc, and the whole then deslimed.

The following examples describe certain tests which have been made in carrying the invention into effect, the reagent proportions in each being figured on the basis of the dry weight tonnage (2000 pounds) of the material treated.

Example 1.Deslimed phosphate feed to plant No. 4 of the Phosphate Recovery Corporation in Florida, consisting mainly of so-called. bone phosphate of lime (tricalcium phosphate) and silica and of a particle size to pass through a screen of 28 meshes to the lineal inch, was made up with water into a thick pulp of about 70% solids. To this pulp were added during agitation in an impeller-type mixer, first 44 lbs. per ton of crude sulphuricacid, the mixer speed being from 300 to 400 R. P. M. Addition of the reagents mentioned required about one minute, subsequent to which agitation in the mixer was continued for about two minutes, small amounts of water being added to maintain a consistency that permitted ready mixing. After this conditioning the pulp was transferred to a laboratory subaeration flotation machine, where it was diluted and agitated for a period of one minute, during which a floating I froth mainly carrying the silica particles was produced and separated. The following table indicates the results of the test:

Example 2.--A sample of the samefeed was processed in the same manner as in Example 1, but in this instance the proportion of the bone oil was increased to 48 lbs. per ton and that of concentrated sulphuric acid decreased to 7.4 lbs. per ton. As shown by the following table, a higher grade of B. P. L. concentrate was obtained, but

Example 3.--Again the identical procedures of Example 1 were repeated, except that 52 lbs. per 4 ton of the bone oil and 3.6 lbs. per ton of the acid were employed, the following results being obtained Parcel my Percent Ratio 0|. Product Egg recovery coneen. a L hm B. P. tratlon d 40.09 48. 18 I-louted M. 1 7. 62 86. 05 10. 3 NOIl-flbatfid 45. 9 78. 36 3- 55 89. 7 l. 96

Example 4.-A sample of the same feed asbefore was made up with water into a pulp of 70% solids, which pulp was agitated in the mixer first with 26 lbs. per ton of crude bone oil obtained from the Eastman Kodak Company and then with 1.84 lbs. per ton of concentrated sul-, phuric acid, the pulp'being acid to litmus after this conditioning operation. As before, the conditioned pulp was treated in the flotation machine for the production of a floating froth, but in this instance, upon removal of the non-floated material (constituting the finished concentrate), the floated material was retreated in the machine, without further addition of reagents. The results are given in the following table, in which the non-floated material obtained by the cleaning operation stated is indicated as a-r'niddling:

Comparative test 1.--A pulp of the same feed and of the same consistency as in the preceding examples was agitated in the mixer with 320 lbs. per ton of crude Eastman Kodak Company bone oil, no acid being employed. Subsequently treating the pulp in the flotation machine, no flotation whatever could be effected.

Example 5.--Deslimed phosphate feed to plant No. 2 of the Prosphate Recovery Corporation in 'Fiorida, also of a particle size to pass through a screen of 2 8 meshes to the lineal inch, was made up with water into a pulp of 70% solids, which pulp was conditioned in the mixer with the following agents separately introduced therein in the order in which they appear: 2.78-lbs. of fuel oil, 34 lbs. of bone oil obtained from Eirner 8: Amend and known as "Animal oil, foetida, tech," and 2.24 lbs. of condentrated sulphuric acid, all per ton of dry feed. The pulp thus conditioned was then processed in the flotation machine in the same manner as in Example 4. The results are shown in the following table, the middling product referring to the non-floated material obtained by retreatment in the machine:

the B. P L. recovery was slightly lowered: Percent assay Percent Product sggfi rigeovery Percent Percent assay Percent Ratio of B. P. L Ins. P 1" Product e1 ht recovery concenw E B P L In: B. P- L.- tratlon li e." gg o Feed 0 39.94 49.72 Mmdnn Flonw 53- 8 8. e2 s7; s3 12. o B Non-floated 4e. 2 16.05 5.51 0 a 06 Non 33.1

were added slowly with stirring. The oil heated 7 Example 6.-A pulp of the same feed as in Example 1 and of the same consistency as before 'was conditioned in the mixer with the following agents separately introduced therein in the order in which they appear: 54 lbs. per ton of concentrated sulphuric acid, 6.24 lbs. per ton of fuel oil, 52 lbs. per ton of crude Texas Chemical Company bone oil, and 0.14 lb. per ton of a frothing agent consisting of 3 parts of crude rosin residue dissolved in 1 part of kerosene oil. Treatment of the conditioned pulp in the flotation machine yielded the following results Example 7.For the purpose of this example caustic soda. was employed in addition to the agents enumerated in Example 6. A pulp of the *same feed as in Example f and of the same consistency as before was conditioned in the mixer, with the following agents separately introduced therein in the order in which they appear: 0.8 lb. of caustic soda, 6.24 lbs. of'fuel oil, 94 lbs. of the same bone oil, 36.8 lbs. of concentrated sulphuricf acid, and 0.28 lb. of the same kerosenerosin frothing agent, all per ton of dry feed. The pulp thusconditioned was treated in the flotation machine, thenon floated material was removed, and the floated material was retreated without further addition of reagents. The resuits are shown in the following table, in which the non-floated material obtained by the cleaning operation stated is indicated as a middling, it being observed that a much higher grade of a B. P. L. concentrate was obtained than in the preceding example:

' Percent assay Percent Product Egg recovery B. P. L. Ins.

Ki. 4 10. 12 85. 97 13. 5 '3. 0 59. 22 26. 89 4. 4 NOIl-fl08fltd 43. G 75. 25 8. 12 82. 1

Example 8.-A pulp of the same feed as in Example l and of the same consistency as before was conditioned in the" same manner as in Example 7, but with the proportions of the bone oil and acid reduced to lbs. per ton and 18.4 lbs'. 'per ton, respectively. Subsequent treatment of the pulp in the flotation machine yielded the fola solution of acid-treated bone oil in alcohol was used as a flotation collector for the silica, which solution was prepared in the following manner: Tb g, of crude Eastman Kodak Company Ii-bone oil, 30 cc. oil-concentrated sulphuric acid Example iii-For the purpose of this example considerably and thickened to a tarry mass, stirring being continued until the oil cooled. The oil thus trcatedwas dissolved in an equal volume of alcohol, the solution being employed in the following test: Y

A'pulp of the same feedas in Example 1 and of the same consistency as before was conditioned in the mixer with the following agents separately introduced therein in the order in which they appear: 0.8 lb. per ton of caustic soda, 6.24 lbs.

per ton of fuel oil, 14 lbs. per ton of the above alcohol solution, and 0.14 'lb. per ton of the lrerosene-rosin frothing agent previously indicated. Subsequent treatment of the pulp in the flotation machine yielded the following results:

, Percent assay eroent Product Per-cent recovery weight B P L B. P. L. Ins. w

Feed 100 40. 13 50. 42 Floated 36.9 6.81 91.54 0.6 Non-floated 63. l 59. 62 26. 37 93. 7

Example 10.-Here a flotation collector was employed consisting of water-soluble constituents of acid-treated bone oil, this collector being obtained as follows:

100 g. of crude Texas Chemical Company bone oil were treated with 30 cc. of concentrated sulphuric acidin the manner indicated in the preceding example. To this treated-oil 100cc. of

water were added, andthe mixture stirred. The

water took much of the products of the treated 1 oil into. solution, the solid material sinking to the bottom of the container. The water solution was decanted and filtered. 1 To the residue another 100 cc. .of water were added with stirring, and the water solution was again decanted and 2 filtered, this procedure being successively re- 'peated until in all 500 cc. of water wereused in leachingthe solid material. The solution obtained by these successive leaching and filtering operations was employed in the following test:

A pulp of the same feed as in Example 1 and of the same consistency as before was conditioned in the mixer with the following agents separately introducedtherein in the order in which they appear: 0.8 lb. per ton of caustic soda, 6.24 lbs.

per ton of fuel oil, a proportion of the above water solution corresponding to 34 lbs. per ton of the constituents dissolved therein, and 0.14 lb. per ton of the kerosene-rosin frothing agent previous'ly indicated. Treatment of the conditioned pulp in theflotation machine yielded the-following results:

Percent assav 1 Percent Product g g recovery 8 I; P L

, B. P. L. Ins.

Feed 100 40.00 50.30 Floated. 42. 8 4. 41 93. 72 4. 7 Non-floated 57. 2 66. 03 17. 82 95. 3

Example 11.--The identical procedures indicated in the preceding example were repeated, except for the following differences: In the preparation of the solution obtained by acid treatment of bone oil and subsequent leaching of the same,

1000 cc. of wash water were employed; and in the flotation test 96 lbs. per ton of the solution crude Eastman Kodak Company bone'oil and alcohol.

thus obtained were employed, without caustic soda. The following results were obtained:

Percent assay Percent Product Per-cent recovery weight B P L B. P. L. Ins.

Feed 100 39. 61 51. 22 Floated 37. 5 3. 41 94. 88 3. 2 N on-floated 62. 5 61. 32 25. 02 96. 8

Percent assay Percent g fl recovery 8 B. P. L

Product B; P. L. Ins.

Comparative test 2.The residue obtained in Example 12 by the acid and water treatment of bone oil was further washed to remove all soluble ingredients. It may here be noted that these ingredients color water intensely so that, as a criterion of their complete removal, washing was continued until the water was colorless. A total of 8500 cc. of 'wash water, including'the 500 cc. employed in Example 12, was required before no coloration could be detected. The residue from this further leaching was then treated with enough alcohol to produce a mixture containing approximately parts of alcohol to 5 parts of residue, most of the residue dissolving in the alcohol. This mixture was filtered and the solution thus obtained employed as a reagent in the following test: v I

A pulp of the same feed as in Example 1 and of the same consistency as before was agitated with the same agents as in Example 12, except that 20 lbs. per ton of the above alcohol solution were employed instead of the water. extract. Subsequently treating the pulp in the flotation machine, substantially no flotation effect was produced on the silica- Example 13. This example isintended to show that the residue obtained by acid and water treatment of bone oil will also cause the silica to float if the soluble ingredients are not all removed.

Crude Texas" Chemical Company bone oil was treated with one-third its weight of concentrated sulphuric acid and the resulting material treated with wash water in amount sufficient to produce a water solution of approidmately 5 parts of dissolved ingredients therein to 95 parts of water, this solution being separated from the residue. To this residue alcohol was added in the approximate mount of 85 parts of alcohol to 15 parts of resfiiue, much of the residue dissolving in the This mixture was being employed in the following test:

A pulp of the same feed as in Example 1 and of the same consistency as before was conditioned in the mixer with the following agents separately introduced therein in the order in which they aDP ar:..0.3 'lb. per ton of caustic soda, 7.5 lbs; per ton of fuel 011,90 cc. per ton of the aboveit being observed that a much ton and 115 which theyappear: 16 lbs.

.trated sulphuric acid, 5.56 lbs.

tioned was treated in the filtered, the filtrate filtrate, and 0.14 lb. per ton of the kerosenerosin frothing agent already described. The pulp thus conditioned was treated in the flotation machine, the non-floated material was removed, and the floated material was retreated without further addition of reagents. The non-floated material resulting from this last operation is indicated as a middling in the following table, higher grade of B. P. L. concentrate was obtained than in Examples 10, 11, and 12, in neither one of which was the leaching of acid-treated bone oil carried out to remove .all water-soluble constituents therefrom.

, Percent assay Percent Product Pal-cent recovery weight B P I B. P. L. Ins.

Feed. L 39. 74 50. 77 Reflontedn 53. 7 10. 12 87. 76 v 13. 7 Middling 4. 0 57. 71 28. 64 5. 8 Non-floated 42. 3 75. 65 5. 88 80. 5

Example 14.Here a flotation collector was prepared by first dissolving 200 g. of crude Texas Chemical Company bone oil in 200 cc. of alco hol. This solution was treated with 250 ccof concentrated sulphuric acid and then with 1000 cc. of water, the resulting material being filtered. I

The filtrate was used in the following test:

A pulp of the same feedas in Example 1 and of the same consistency as before was conditioned in the mixer with the following agents separately introduced therein in the. order in whichthey appear: 0.6 lb. of caustic soda, 2 lbs. of fuel oil, 100 cc. of the above filtrate, and 0.14 lb. of the kerosene-rosin frothing agent already indicated, all per'ton of dry feed. Subsequently treating the pulp in the flotation machine, a concentrate 'as'a non-floated material was obtained assaying 51.13% B. P. L., the B. P. L. recovery being 98%. Example 15.Repeating the identical proce-- dures of Example 14, but with the proportions of the fuel oil and filtrate increased cc. per ton, respectively, the nonfloated material assayed 57.63% B. P. L., the B. P. L. recovery being 97.7%.

Example 16.Here crude quinoline derived from coal tar and-obtained from the Eastman Kodak Company was used as a flotationcollector for the silica, the test being carried out as follows: -A pulp of the same feed as in Example 1 and of the same consistency as before was conditioned in the mixer with the following agents separately introduced therein in the order in per ton of the above quinoline .material, 3.68 lbs. per tonof concenper ton of fuel oil,-1.84 lbs. per ton more of concentrated sulphuric acid, and 12 lbs. per ton more of the The pulp thus condiflotation machine, the non-floated material was removed, and the floated material was retreated without further addition of reagents, the nomfloated. material obtained by this cleaning as a middling in the following table:

above quinoline material.

Percent assay 7 ,Percent Percent weight Product to 4 lbs. per

operation being indicated amazes Example 17.-A much higher grade of'concentrate was obtained with crude quinoline by the following procedures:

To a pulp of the same feed as in Example 1 and of the same consistency as before were added, during agitation in the mixer, first 22 lbs. per ton of crude quinoline and then 3.68 lbs. per ton of concentrated sulphuric acid. The pulp thus conditioned-was transferred to the flotation machine, where subsequent to dilution 7.2 lbs. per ton of kerosene were introduced through the air duct and a sand float removed in the usual manner by agitation. Thereafter, 7.2 lbs. per ton of kerosene were once more introduced through the air duct and a second sand float removed. The results of the test are indicated in the following table:

Percent assay P ercent Product Per-cent recovery weight B P L B. P. L Insl 40.0 4.5 Non-floated 55. 5

In each of the following ten examples acid other than sulphuric acid was used as an activating agent.

Example 18.-A pulp of the same feed as in Example 1 and of the same consistency as before was agitated in the mixer first with 48 lbs. of

crude Texas Chemical Company bone oil and then with 10 lbs. of glacial acetic acid, both per ton of dry feed. Subsequent treatment of the pulp .in the flotation machine yielded the following Example 19.--The procedures employed werethe same as in the preceding example, except that the proportion of acetic acid was reduced to 6 lbs. per ton and the floated material retreated in the flotation machine, the non-floated material obtained by the latter operation being indicated as a middling in the following table:

Pemmt assay ercent Ratio of Product 35 r covery conceng B L P. tration Example 20.-'.By further reducing the proportion of the acetic acid of Example 18 to 4 lbs. per ton, but otherwisefollowing the identical procedures of that example, the following results were obtained:

Example 21.A pulp of the same feed as in Example 1 and of the same consistency as before was agitated in the mixer first with 10 lbs) of crude Eastman Kodak Company bone oil and then with 1.6 lbs. of hydrofluoric acid, both per ton of dry feed. Subsequent treatment of the pulp in the flotation machine yielded the following results:

Percent assay Percent IBCOVBIY B. P.

Percent weight Product B. P. L. Ins.

Example 22.-Here the activating agent was hydrofluorsilicic acid, obtained from Eimer & Amend as a solution of 27% to 28% acid strength. To a pulp of the same feed as in Example 1 and of the same consistency as before were added, during agitation in the mixer, first 8 lbs. per ton of crude Eastman Kodak Company bone oil and then an amount of the above solution corresponding to 0.8 lb. per ton of the hydrofluorsilicio acid dissolved therein, subsequent treatment of the pulp in the flotation machine yielding the following results:

Percent assay Product B. P. L. Ins.

50. 93. Non-floated.--" 5.

Example 23.A pulp of the same feed as in Example 1 and of the same consistency as before was agitated in the mixer first with 8 lbs. of crude Eastman Kodak Company bone oil and then with 8 lbs. of chemically purearsenic acid, both per ton of dry feed. Subsequent treatment of the pulp yielded the following results:

Product B. P. L. Ins.

Non-floated Example 24.-A pulp of the same feed as in Example 1 and of the same consistency as before was agitated-in the mixer first with 8 lbs. of crude Eastman Kodak Company bone oil and 5.6 lbs.

of chemically pure selenic acid, both per ton of dry feed. Subsequent treatment of the pulp in the flotation machine yielded the following results:

Percent assay Percent Per-cant recovery B. P. L.

Product B. P. L. Ins.

Floated.

l 40. 10 49. e 5. 21 93. 14 e. 4 Non-floated 50. 4 74. 45 8. 45

Example 25.A pulp of the same feed as in Example 1 and of the same consistency as before was agitated in the mixer first with 40 lbs. of crude 1 Texas Chemical Company bone oil and then with lbs. of lactic acid, both per ton of dry feed.

the usual manner.

Subsequent treatment of the pulp in the flotation machine yielded the following results:

of the pulp in the flotation machine yielded the following results:

Percent assay m t P er-cent assay PM Product W l'ggovb y Product 'fifl recovery Weight B P L B. P. L.

B. P. L. Ills. B. P. L. I.

. FM 100 38.81 51.15 i$t&::::::::::::::::::::. 1 %?3 3.3 Floatod as m. 00.47 9.; Non-floated 51.3 75.17 3,04 9 ,7 Non-floated 45.7 77.17 4.43 90.:

of dry feed.- The pulp was then transferred to the flotation machine, where it was treated in The B. P. L. assay of the non-floated material was 78.48% and the B. P. L. recovery therein 91.3%.

Example 27.The activating agent in this instance was sulphurous acid formed by bubbling sulphur dioxide gas through water. A pulp of the same feed as in Example 1 and of the same consistency as before was conditioned first with 30.2 lbs. per ton of crude Texas Chemical Company bone land then with an undetermined amount of he aboye formed acid. Subsequent frothing of the pulp yielded a non-floated material assaying 73.35% B. P. L., the B. P. L.'recovered therein being 94.9%.

Inorganic salts were employed as activating agents in the following fifteenexamples.

Example 28.-A pulp of the same feed as in Example 1 and of the same consistency as before was agitated in the mixer first .with 8 lbs. per ton of crude Eastman Kodak Company bone oil and then with 0.8 lb. per ton of sodium silicofluoride as a 2.5% solution in water; Subsequent treatment of the pulp in the flotation machine yielded the following results:

I Examplezils-A pulp of the same feed asin Example 1 and of the same consistency as before was agitated in the mixer first with lbs. per ton of crude Eastman Kodak Company bone oil and then with 1. lb. per ton of ammonium silicofluoride as a 2.5% solution in water. Sub-, sequent treatment of the pulp in the flotation Example 1 and of the same consistency as before was agitated in the'mixer first with 20 lbs. per ton of crude Eastman Kodak Company bone oil and then with 4 lbs. per ton of stannic chloride as a 5% solution in water. Subsequent treatment Company bone oil.

Example 31.A sample of the same feed as in Example 1 was subjected to froth flotation with 16 lbs. per ton crude Eastman Kodak Company bone oil and 4 lbs. per ton of stannous chloride. While the non-floated material assayed 76.36% B. P. L., the B. P. L. recovery therein was only 11.2%. v

Example 32.A pulp of the same. feed as in Example 1 and of the same consistency as before was agitated in the mixer first with 20 lbs. per ton of crude Eastman Kodak Company bone oil and 8 lbs. pertonof silicon tetrachloride. Subsequent treatment of the pulp in the flota- Example 33.-A sample of the same feed as in Example 1 was subjected to froth flotation with 54 lbs. per ton of crude Eastman Kodak Company bone oil and 20 lbs. per ton, of nickel sulphate. The B. P. L. assay of the non-floated material was 79.02%, but the B. P..L. recovery was only 20%.

Example 34.A sample of the same feed as in Example 1 was subjected to froth flotation with 20 lbs. per ton of crude Texas Chemical Company bone oil and 4 lbs. per ton of zinc sulphate. The B. P. L. assay of the non-floated material was 75.66%, but the B. P. L. recovery was only 17.6%.

Example 35.'-A pulp of the same feed as .in Example 1 and of the same consistency as before was agitated in the mixer first with 64.52 lbs.

per ton oi. phosphorus trichloride and then with 30.2 lbs. per ton of crude Texas Chemical Company bone oil. Subsequent treatment of the pulp in the flotation machine yielded the following results: J

Example 36.A pulp of the same feed as in Example 1 and of the same consistency as be fore was agitated inthe mixer first with 64 lbs. per ton of phosphorus pentachloride and then with 30.2 lbs.- per ton of crude Texas Chemical By subsequenttreatment of the pulp in the flotation machine a non-floated material was obtained assaying 57.66% B. P. L, the B. P. L. recovered therein being 89.4%.

Example 37.--A pulp of the same feed as in Example 1 and of the same consistency as before was agitated in the mixer first with 20 lbs.

per ton of cupric chloride and then with 30.2

lbs. per ton of crude Texas Chemical Company 5 bone oil. By subsequent treatment of the pulp in the flotation machine a non-floated material was obtained assaying 53.56%. B. P. L., the B. P. L. recovered therein being 71.7%.

Example 38.A pulp of the same feed as' in Example 1 and of the same consistency as before was agitated in the mixer first with 30.2 lbs. per ton of crude Texas Chemical Company bone oil and then with 3.36 lbs. per ton of thionyl chloride. Subsequent treatment of the pulp in the flotation machine yielded the following results:

Percent assay 1, t Product 25mg [8553 8 1 13. P. L. Ins.

100 41.45 50.5 6.93 8.4 Non-floated 49.5 76.67 7 2 91.6

Example 39.-A pulp of the same feed as in Example 1 and of the same consistency as before was agitated in the mixer first with 68 lbs. per ton of crude Texas Chemical Companybone oil and then with 40 lbs. per ton of potassium bisulphate. Subsequent treatment of the pulp inthe flotation machine yielded the following results:

Perce tassa Product 353,1 n y 535%;

B. P. L. Ins.

Feed.... Q 100 40.66 Floated.. 46. 9 4. 67 5.4 Non-float 53.1 72.45 10.71 94.6

Example 40.A sample of the same feed as in Example 1 was subjected to froth flotation with 68 lbs. per ton of crude Texas Chemical Company bone oil and 40 lbs. per ton of sodium dihydrogen phosphate. While the B. P. L. assay of the nonfloated material was only 50.34%, the B. P. L. recovered therein was 95.1%.

Example 41.A pulp of the same feed as in Example 1 and of the same consistency as before was conditioned with 44 lbs. per ton .of crude quinoline, 6.48 lbs. per ton of sulphur monochloride, and 7.2 lbs. perton of kerosene. Subsequent frothing of the pulp yielded the following results:

, Example. 42.--A sample of the same feed as in Example 1 was subjected to froth flotation with 22 lbs. per ton of crude quinoline, 6.72 lbs. per ton of thionyl chloride, and 7.2 lbs. per ton of kerosene. The B. P. L. assay of the non-floated material was 59.08% .and the B. P. L. recovery therein 92.8%.

70 In an endeavor to determine the effect of fuel .oil on the process of the present invention the following tests were carried out:

Example 43.-A pulp of the same feed as in Example 1 and of the same consistency as be'-.

15 fore was conditioned in the mixer with the 1'01- lowing agents separately introduced therein m the order inwhich they appear: 3 pounds of fuel oil, 16 pounds of crude Eastman Kodak Company bone oil, 93nd 1.84 pounds of concentrated sulphuric acid, all per ton of dry feed. Subsequent treatment of the pulp in the flotation machine yielded a concentrate as a non-floated material assaying 78.77% B. P. L., the B. P. L. recovery being 77.3%. I

Example 44.-Repeating the procedures of Example 43, but with the proportion of fuel 011 decreased to 2 pounds per ton, the B. P. L. assay of the non-floated material was 77.05% and the B. P. L. recovery 86.0%.

Example 45.--Here no fuel oil was employed, the procedures being otherwise the same as in Example 43, the bone oil being added before the acid. The non-floated material assayed 76.16%

B. P. L., the B. P. L. recovery being 90.4%.

The percent assays and recoveries obtained in Examples 43, 44', and 45 are recorded in the following table, from which it is seen that the effect of fuel oil is to increase the grade of concentrate, but to lower the recovery:

Percent Percent assay recovery B. P. L. B. P. L.

The effect produced by employing different amounts of bone oil was also investigated, the following test being carried out for comparison with Example 43.

Example 46.-The conditions were the same as in Example 43, except that the proportion of bone oil was decreased to 10 pounds per ton. The non floated material assayed 63.82% B. P. L., the B. P. L. recovery being 79.8%.

The following table records the percent assays and recoveries obtained in Examples 43 and 46, it being observed that. the grade of concentrate increases and the recovery decreases, with increasing amount of. bone oil:

Experimental work was also carried out with fuel oil, bone oil, and acid to determine the effect of the order of addition of these agents, the following tests being carried out for comparison with Example 44:

Example 47.-The procedures were the same as in Example 44, but here the bone oil was introduced before the fuel oil, the acid being introduced last. The non-floated material assayed 77.85% B. P. L., the B. P. L. recovery being 78.9%.

Example 48.--H ere the acid was introduced first, then the fuel oil, then the bone oil, the procedures being otherwise the same as in Example 44. The non-floated material assayed 51.47%

B. P. L., the B. P. L. recovery being 75.6%.

The percent assays and recoveries obtained in Examples 44, 47, and 48 are recorded in the table below. From this table it is apparent that the bone oil should be added before the acid in order to obtain best results with regard to both grade of concentrate and recovery. As to the fuel oil, it should be added before the bone oil in order to obtain the highestgrade of concentrate,

and after ,the bone oil in order to obtain the highest recovery:

lst 2nd agent 3rd t m t 11 ans recov Ex. FuoloiL. BoneoiL- Acid..-" 77.05 86.0

Ex. BoneoiL. FueloiL- Acid..-" 77.86 78.9

Ex.48 Acid-.- FueloiL. BoneoiL. 51.41 75.6

With the view to determine what the eifect might be by diluting the acid prior to introduction into the mixer, the following test was carried out for comparison with Example 44:

Example v49.---The procedures were the same as in Example 44, but here the acid was introduced as a 5% solution. The .non-fl ted material assayed 78.7'1% B. P. L. the B. R 3. recovery being 79.8%.

The percent assays and recoveries obtained in Examples 44 and 49 are recorded in the following table it being apparent that the use of concentrated acid lowers the grade of concentrate and increases the recoverypand that the use of dilute acid increases the grade of concentrate and lowers the recovery.

Percent Percent assay recov B. P. L. B. R i 4 Ex. 44 (concentrated acid)" 77. 05 80. 0 Ex. 49 (diluted acid) 78. 77 79. 8

The following examples are intended to show the applicability of the process of the invention to tabling.

Example 50.-A pulp of the same feed as'in Example 1 and of the same consistency as before was conditioned in the mixer with the following agents separately introduced therein in the order in which they appear: 30 pounds per ton of crude Texas Chemical Company bone oil and 10 pounds per ton of acetic acid. These agents were added to the pulp during agitation, this addition requiring about one minute and agitation being thereafter continued for two minutes more. Subsequent to this conditioning, the pulp was fed to a laboratory-size Wilfley table with the results in-' dicated in the following table, wherein the product termed "Tailing refers to the material which came all the side of the table near; the feed end, the product termed Concentrate refers to the material which in large part came off the discharge end, and the product termed Middling refers to the material which came off the side between the concentrate and tailing products.

Percent Percent Percent Baa. as"? herein should be interpreted as limiting the in- Percent assay PM 5 recovery 13. P. L.

Percentt B. P. L. Ins.

Example 52.A sample of the same feed as in Example 1 was subjected to a tabling operation with 14.4 lbs. per ton of kerosene, 65.7 lbs. per ton. of crude quinoline, and 24 lbs. per ton of acetic acid. The material which came of! the discharge end of the table assayed 76.57% B. P. L.

None of the procedures described in detail vention, these procedures being capable of being modified in many ways without departing from the spirit of the invention.

What is claimed is:

1. The process of concentrating phosphatebearing minerals which consists in agitating a pulp of the ore containing the phosphate-bearing mineral first with crude quinoline and thereafter with an activating agent causing the crude quinoline to have a preferential aflinity for the silicious gangue, said activating agent being an inorganic salt capable of reacting acid in solution withwater, separatingfrom the pulp a material relatively rich in silicious gangue and relatively poor in phosphate values, and collecting the remaining material as the concentrate.

' 2. The process of concentrating phosphatebearing minerals which consists in agitating a pulp of the ore containing the phosphate-bearing mineral first with bone oil and thereafter with an activating agent causing the bone oil to have a preferential aifinity for the silicious gangue, said activating agent being an inorganic salt capable of reacting acid in solution with water, separating from the pulp a material relatively rich in silicious gangue and relatively poor in phosphate values, and collecting the remaining material as the concentrate.

3. The process of concentrating phosphatebearing minerals which consists in agitating a pulp of the ore containing the phosphate-bearing mineral with mineral oil, crude quinoline, and an activating agent causingthe crude quinoline to have a preferential aiiinity for the silicious gangue, said actuating agent being an inorganic salt capable of reacting acid in solution with water, separating from the pulp a material relatively rich in silicious ,gangue and relatively poor in phosphate values, and collecting the remaining material as the concentrate. 60

4. The process of concentrating phosphatebearing minerals which consists in agitating pulp of the ore containing the phosphate-bearing mineral with mineral oil, bone oil, and an activating agent causing the bone oil to have a preferen- 5 tlal aflinity for the silicious gangue, said activating agent being an inorganic salt capable of re acting acid in solution with water, separating from the pulp a material relatively rich in silicious gangue and relatively poor in phosphate values. and collecting the remaining material as the concentrate.

5. The process of concentrating phosphatebearing minerals which consists in agitating a pulp of the ore containing the phosphate-bearing 7 mineral in the presence of crude quinoline and an activating gent causing the crude quinoiine to have 9. pr ferentlal aillnity (or the silicious gangue, said activating agent being an inorganic salt capable oi reacting acid in solution with water, treating the pulp so as to cause a float relatively rich in silicious gangueand relatively poor in phosphate values, and collecting the noniloated material as the concentrate.

6. The process of concentrating phosphatebearing minerals which consists in agitating a pulp of the ore containing the phosphate-bearing mineral in the presence of bone oil-and an activating agent causing the bone oil to have a preferential afllnlty for the silicious gangue. said activating agent being an inorganic salt capable of reacting acid in solution with water, treating the pulp so as to cause a float relatively rich in silicious gangue and relatively poor in phosphate values, and collecting the non-floated material as the concentrate.

.7. The process of concentrating phosphatebearing minerals which consists in agitating a pulp of the ore containing the phosphate-bearin mineral in the presence of crude quinoline and an activating agent causing the crude quinoiine to have a preferential aflinity for the silicious gangue, said activating agent being an inorganic salt capable of reacting acid in solution with water, and treating the pulp on a shaking table so as to separate the silicious gangue from the phosphate values.

8. The processof concentrating phosphatebearing minerals which consists in agitating ii.

pulp of the ore containing the phosphate-bearing mineral in the presence'o! bone oil and an activating agent causing the bone oil to have a preterential amnity tor the silicious gangue, said acti-' vatingagent being an inorganic salt capable of reacting acid in solution with water, and treating the pulp on a shaking table so as to separate the silicious gangue from the-phosphate values.

9. The process of concentrating phosphatebearing minerals which consists in agitating a pulp oi the ore containing the phosphate-bearing mineral in the presence of crude quinoline and an activatin agent causing the crude quinoline to have a preferential aiilnity for the silicious gangue, said activating agent being an inorganic salt capable oi reacting acid in solution with water, separating from. the pulp a material relatively rlchin silicious gangue and relatively poor in phosphate values. and'collecting the remaining and collecting the remainingmaterial as the' concentrate.

11. The oi concentrating phosphatebearing minerals which consists in-agitating a pulp oi the ore containing the phosphate-bearing mineral in the presence of crude quinoline and an sctivaflns agent causing the crude quinoline to have a amnity tor the silicious gangue, said activating agent inorganic halide salt capable of reacting acid in solution with water. separating from the pulp a ma relatively rich in silicious gangue and relatively poor in phosphate values, and collecting the remaining material as the concentrate.

12. The process of concentrating phosphatebearing minerals which consists in agitating a pulp of the are containing the phosphate-bearing mineral in the presence of bone oil and an activating agent causing the bone oil to have a preferential ailinity for the silicious gangue, said activating agent being an inorganic halide salt capable of reacting acid in solution with water, separating from the pulp a material relatively rich-in silicious gangueand relatively poor in phosphate values, and collecting the remaining material as the concentrate.

13. The process of concentrating phosphatebearing minerals which consists in agitating a pulp of the ore containing the phosphate-bearing mineral in the presence of crude quinoline and an activating agent causing the crude quinoline to have a preferential aillnity for -the silicious gangue, said activating agent being an inorganic chloride salt capable of reacting acid in solution 'mineral in the presence of bone oil and an activating agent causing the bone oil to have a preferential afllnity for the silicious ga ue, said activating agent being an inorganic chloride salt capable of reacting acid in solution with water, separating from the'pulp a material relatively rich in silicious gangue and relatiyely poor in phosphate values. and collecting-the remaining material as the concentrate.

15. The processoi' concentrating phosphatebearing minerals which consists in agitating a pulp of the ore containing the phosphate-bearing mineral in the presence '01 bone oil and an activating agent causing thebone oil to have a preferential amnity for the silicious gan ue. said activating a ent being an alkali metal silicofluoride capable of reacting acid in solution with water, separating from the pulp a material relatively rich in silicious gangue and relatively poor in phosphate values, and collecting the remaining material as the concentrate.

16. The process of concentrating phosphate bearing. minerals which consists in agitating a pulp or the ore containing the phosphate-bearing mineral in the oi. crude quinoline and an acid capable of forming with water a distinctly acidsolution readily titratable with an aqueous solution of a base, separating from the pulp a material relatively rich in silicious gangue and relatively poor in phosphate values, and collecting the remaining material as the concentrate.

. 17. The process of concentrating. phosphate- .bearing'. which consists in agitating a A u1p ;ot the. ore. containing ,the phosphate-bearing mineral in the presence of bone oil andian acid -capable of forming with water a distinctly acid solution titratable'with' an aqueous solution of a base, irointhe pulp a material relatively rich in silicious gangue and relatively poor in phosphate values, and collecting the remaining material as the concentrate.

' 18. The process of concentrating phosphatebearing minerals whichnoonsists in agitating a of the ore containing the phosphate-bearing mineral in the at acid treated bone oil.

the oil-treating acid being capable of forming with water a distinctly acid solution readily titratable with an aqueous solution of a base, separating from the pulp a material relatively rich in silicious gangue and relatively poor in phosphate values, and collecting the remaining material as the concentrate.

19. The process of concentrating phosphatebearing minerals which consists in, agitating a pulp of the ore containing the phosphate-bearing mineral in the presence of an alcoholsolution of acid-treated bone oil, the oil-treating acid being capable of forming with water 'a distinctly acid solution readily titratable with an aqueous solution of a base, separating from the pulp a material relatively rich in silicious gangue and relatively poor in phosphate values, and collecting the remaining material as the concentrate.

20. The process of concentrating phosphatebearing minerals which'consists in agitating a pulp of the ore containing the phosphate-bearing mineral first with bone'oil andthereaiter with an acid capable of forming with water a distinctly acid solution readily titratable with an aqueous solution of a base, separating from the pulp a material relatively rich in silicious "gangue and relatively poor in phosphate values, and

the remaining material as the concenbearing minerals which consists in agitating a Pulp of the ore containing the phosphate-bearing mineral with fuel oil, bone oil, and an acid capable oiiorming with water a distinctly acid solution readily titratable with an aqueous solution of a base, separating from the pulp a material relatively rich in silicous'gangue and relatively poor-in phosphate values, "and collecting the remainingmaterial as the concentrate.

23. The process or concentrating phosphate bearing minerals which consists in agitating a pulp of the ore containing the phosphate-bears ing mineral with fuel oil, bone oil, and anacid capable of forming with water a distinctly acid solution readily titratable with an aqucous'solution of a base, the bone oil being added before the acid, separating from the pulp a material relatively rich in silicious ganglia and relatively poor in phosphate values, and collecting the remain-.-

ing material as the concentrate.

24. The process of concentrating phosphate-- bearing minerals which consists in agitating a pulp of the ore containing thephosphate-bearing mineral with fuel oil, bone oil, and an acid capabio of forming with water a distinctlyacid solution readily titratable with an aqueous solution of a base, the 'bone oil being before. the.

acid and after the fuel oil, separating from the pulp amaterial relatively rich. in silicious gangue and relative y P9 inphosphate-values, and collecting the'remaining material as'the concen- 25.: The process oi concentrating bearing minerals which consists in agitating a pulp of the ore containing the phosphate-bearing mineral with fuel oil, bone oil, and an acid capable of forming with water a distinctly acid solution readily titratable with an aqueous solution of a base, the bone'oil being added before the acid and fuel oil, separating from the pulp a material relatively rich in silicious gangue and relativelypoor in phosphate values, and collecting the remaining material as the concentrate.

'26. The process of concentrating phosphatebearing minerals which consists in agitating a pulp of the ore containing the phosphate-bearing mineral in the presence of crude quinoline and sulphuric acid, separating from the pulp a material relatively rich in silicious gangue and poor in phosphate values, and collecting the remaining material as the concentrate.

' 28. The process of concentrating phosphatebearing' minerals which consists in agitating a pulp of the ore containing the phosphate-bearing mineral in the presence of sulphurlc-acidtreated bone oil, separating from the pulp a material relatively rich in silicious gangue and relatively poor in phosphate values. and collecting the remaining material as the concentrate.

29. The process of concentrating phosphatebearing minerals which consists in agitating a pulp of the ore containing the phosphate-bearing mineral in the presence voi water-soluble constituents of sulphuric-acid-treated bone oil, separating from the pulp is material relatively rich in silicious gangue and relatively poor in phosphate values, and collecting the remaining material as the concentrate.

30. The process of concentrating phosphatebearing minerals which consists in agitating a pulp of the ore containing the phosphate-bearing mineral in the-presenoe-ot bone oil and acetic acid, separatlng from the pulp a material relatively rich in silicious gangue and poor in phosphate values. and collecting the remaining.

material as the'concentrate.

31. The process of conccntrating'phosphatewhich consists in agitating a pulp oi'theore containing the phosphate-bearing unineral in the presence of andhvdrofluoric acid, separating from the pulp a material relatively rich in silicious gangu'e and relatively poor in phosphate values, and collecting the remainingmaterial as the concentrate,

1 32. The process concentrating phosphatebearing minerals which consists'in agitating a pulp of the ore containing the phosphate-'bearing mineral in the presence of crude-quinoline and an acid capable of forming with water a distinctly acid solution readily titratable with an aqueous soifitionoi a base, treating the pulp so as to cause a float relatively rich in sllicious gangue and relatively poor in phosphate values, and collecting the non-floated as the '33. The process of concentrating phosphate-' bearing which consists in agitating a pulp or the ore containing the phosphate-bearing mineralin the presence or bone oil and an acid capabieottorming with a distinctly-acid aromas solution readily titratable with an aqueous solutionotabasetreatingthepulpsoastocausea float relatively rich in silicious gangue and relatively poor in phosphate values, and collecting the non-floated material as the concentrate.

34. The process of concentrating phosphatebearing minerals which consists in agitating a pulp oi the ore containing the phosphate-bearing mineral in the presence 01' acid-treated bone oil, the oil-treating acid being capable of forming with water a distinctly acid solution readily titratable wlth'an-aqueous solution of a base, treating the pulp so as to cause a float relatively rich in silicious gangue and relatively poor in phosphate values, and collecting the non-floated material as the concentrate.

35. The process of concentrating phosphatebearing minerals which consists in agitating a pulp of the ore containing the phosphate-bearing mineral in the presence of water-soluble constituents of acid-treated bone oil, the oil-treating acid being capable of forming with water a distinctly acid solution readily titratable with an aqueous solution or a base, treating the pulp so as to cause'a float relatively rich in silicious gangue and're'latively poor lnphosphate values, andcollecting the non-floated material as the concentrate.

. 36. The process of concentrating phosphatebearing minerals which consists in agitating a pulp of the ore containing the phosphate-bearing mineral in the presence of crude quinoline and an acid capable of forming with water 'a distinctly acid solutionreadily titratable with an aqueous solution of a base, and treating the pulp on a shaking table so as to separate the silicious,

gangue from the phosphate values.

Patent No 2,103, 285

37. The process oi! concentrating phosphate- CERTIFICATE bearing minerals which consists in agitating a pulp or the ore containing the phosphate bearing mineral in the presenceoi bone oil and an acid capable of forming with water a distinctly acid solution readily titratable with an aqueous solution of a base, and treating the pulp on a shaking table so as to separate the silicious game from the phosphate values.

38. The process of concentrating phosphate-' bearing minerals which consists in agitating a pulp of the ore containing the phosphate-bearing mineral in the presence of acid-treated bone oil, the oil-treating acid being capable or forming with water a distinctly acid solution readily titratable with an aqueous solution of a base, and treating 'the pulp on a shaking table so as to separate the silicious gangue from the phosphate values.

39. The process of concentrating phosphate bearing minerals which consists in agitating a* pulp of the ore containing the phosphate bearing' mineral in the presence of water-soluble constituents oi. acid-treated bone oil, the oil-treat acid being capable of forming with water a distinctly acid solution readily titratable with an aqueous solution of a base, and treating the pulp on a shaking table so as to separate the silicious gangue from the phosphate values. 7

40. The process of concentrating phosphatehearing minerals which consists in agitating a pulp of the ore containing the phosphate-bearing mineral in the presence of bone oil and sulphuric acid, treating the pulp so as to cause a float relatively rich in silicious gangue and relatively poor in phosphate values, and collecting the non-floated material as the concentrate.-

' FRANCIS X. 'TARTAROK JAMES B. DUKE.

December 8 minors x. TARTARON, ET AL.

It is hereby certified that error appears. inv the. printed specification of the-above numbered patent requiring correction as follows Pages, second column-,line 55, claim 5, for the word "actuating" read activating: and that the said Letters Patent should beread with this correction therein that the same may conform to the record of the ease in the Patent Office;

(Seal) Signed and sealed this 22nd day of February, ,A. n. 1953.

Henry Van Arsdale,

Acting Commissioner of Patents.

aromas solution readily titratable with an aqueous solutionotabasetreatingthepulpsoastocausea float relatively rich in silicious gangue and relatively poor in phosphate values, and collecting the non-floated material as the concentrate.

34. The process of concentrating phosphatebearing minerals which consists in agitating a pulp oi the ore containing the phosphate-bearing mineral in the presence 01' acid-treated bone oil, the oil-treating acid being capable of forming with water a distinctly acid solution readily titratable wlth'an-aqueous solution of a base, treating the pulp so as to cause a float relatively rich in silicious gangue and relatively poor in phosphate values, and collecting the non-floated material as the concentrate.

35. The process of concentrating phosphatebearing minerals which consists in agitating a pulp of the ore containing the phosphate-bearing mineral in the presence of water-soluble constituents of acid-treated bone oil, the oil-treating acid being capable of forming with water a distinctly acid solution readily titratable with an aqueous solution or a base, treating the pulp so as to cause'a float relatively rich in silicious gangue and're'latively poor lnphosphate values, andcollecting the non-floated material as the concentrate.

. 36. The process of concentrating phosphatebearing minerals which consists in agitating a pulp of the ore containing the phosphate-bearing mineral in the presence of crude quinoline and an acid capable of forming with water 'a distinctly acid solutionreadily titratable with an aqueous solution of a base, and treating the pulp on a shaking table so as to separate the silicious,

gangue from the phosphate values.

Patent No 2,103, 285

37. The process oi! concentrating phosphate- CERTIFICATE bearing minerals which consists in agitating a pulp or the ore containing the phosphate bearing mineral in the presenceoi bone oil and an acid capable of forming with water a distinctly acid solution readily titratable with an aqueous solution of a base, and treating the pulp on a shaking table so as to separate the silicious game from the phosphate values.

38. The process of concentrating phosphate-' bearing minerals which consists in agitating a pulp of the ore containing the phosphate-bearing mineral in the presence of acid-treated bone oil, the oil-treating acid being capable or forming with water a distinctly acid solution readily titratable with an aqueous solution of a base, and treating 'the pulp on a shaking table so as to separate the silicious gangue from the phosphate values.

39. The process of concentrating phosphate bearing minerals which consists in agitating a* pulp of the ore containing the phosphate bearing' mineral in the presence of water-soluble constituents oi. acid-treated bone oil, the oil-treat acid being capable of forming with water a distinctly acid solution readily titratable with an aqueous solution of a base, and treating the pulp on a shaking table so as to separate the silicious gangue from the phosphate values. 7

40. The process of concentrating phosphatehearing minerals which consists in agitating a pulp of the ore containing the phosphate-bearing mineral in the presence of bone oil and sulphuric acid, treating the pulp so as to cause a float relatively rich in silicious gangue and relatively poor in phosphate values, and collecting the non-floated material as the concentrate.-

' FRANCIS X. 'TARTAROK JAMES B. DUKE.

December 8 minors x. TARTARON, ET AL.

It is hereby certified that error appears. inv the. printed specification of the-above numbered patent requiring correction as follows Pages, second column-,line 55, claim 5, for the word "actuating" read activating: and that the said Letters Patent should beread with this correction therein that the same may conform to the record of the ease in the Patent Office;

(Seal) Signed and sealed this 22nd day of February, ,A. n. 1953.

Henry Van Arsdale,

Acting Commissioner of Patents. 

